$bg:green;

body{
    display: flex;
    justify-content: center;
    background-color:$bg;
}

#img{
    width: 80px;
    height: 80px;
    background: url('../images/index_img.png') no-repeat 100% 100%;
}
#img2{
    width: 80px;
    height: 80px;
    background: url('../images/zs_img.png') no-repeat 100% 100%;
}